I have had 12 in a class (loud rendition of "oh, happy day!") and I have had over 45. (singing abruptly comes to screeching halt and I lose my sense of humor when I need it most) I am lucky because with upper grades I can use the "you need this class to finish" argument. "If you make it difficult for your classmates to succeed I will not tolerate you in my class and you will need to take it elsewhere." (out of our school) This usually stops the class clowns from teetering over the edge into class knuckleheads. And yes to groupwork, groupwork, groupwork. Class discussions are often done in 4 tops with share out afterwards, peer editing is also done in 4 tops, as are lots of other stuff. By 4 top I have them at two tables where front table can swing around to talk to back table so it is easy to transition from whole class, to table partner or group of 4. Each member has a letter (A-D) and a role that goes with that letter for the day. But yeah, give me tiny classes any day. HUGE difference.